Corporate Banner
Satellite Banner
Food & Beverage Analysis
Scientific Community
Become a Member | Sign in
Home>News>This Article

Dairy Researchers Identify Bacterial Spoilers in Milk

Published: Wednesday, July 18, 2012
Last Updated: Wednesday, July 18, 2012
Bookmark and Share
Research from Cornell food scientists can be used to protect the quality and shelf life of dairy products.

Milk undergoes heat treatment -- pasteurization -- to kill off microbes that can cause food spoilage and disease, but certain bacterial strains can survive this heat shock as spores and cause milk to curdle in storage.

Researchers in the Milk Quality Improvement Program at Cornell's College of Agriculture and Life Sciences have identified the predominant spore-forming bacteria in milk and their unique enzyme activity.

"Control of food spoilage is critical in a world that needs to feed 7 billion people," said Martin Wiedmann, food science professor and study co-author. "Approximately 25 percent of post-harvest food is spoiled by microbes before it is consumed."

The study, published in the March issue of Applied Environmental Microbiology by the lab of Wiedmann and Kathryn Boor, the Ronald P. Lynch Dean of the College of Agriculture and Life Sciences, identified the predominant strains of spore-forming bacteria, which can foul milk and other food products. The culprits, Paenibacillus bacteria, are ubiquitous in nature and cause off-flavors in a variety of foods and curdling in dairy products.

As spores, the bacteria can survive in dormant form for years despite the best practices in cleaning, processing and packaging.

In fact, the bacteria may be uniquely adapted to overcome the twin tactics of dairy protection: pasteurization followed by refrigeration. According to co-author and research support specialist Nicole Martin, the spores are not only resistant to heat, the small jolt of heat during pasteurization may actually stimulate them to germinate. Some can reproduce in refrigerated dairy products at temperatures that would stymy other types of bacteria.

"We studied 1,288 bacterial isolates in raw milk, pasteurized milk and the dairy farm environment; however, only a handful of strains accounted for 80 percent of the spore-formers present," said Wiedmann. "They grow well in milk -- and possibly other foods -- at temperatures as low as 43 F, and we can identify Paenibacillus because of their uniquely high galactosidase enzyme activity at 32 C."

They also investigated how pasteurization affects the presence of such bacteria.
Concerns about food safety have prompted many dairy processors to increase pasteurization temperatures above the 161 F minimum set by the government. Anecdotal reports, however, suggested this practice actually led to more spoilage once the products were refrigerated.
Tallying bacterial numbers throughout the refrigerated shelf life of milk pasteurized at two different temperatures -- 169 F and 175 F -- the Wiedmann-Boor lab found that lowering the temperature significantly reduced bacterial growth during refrigerated storage, especially by 21 days after pasteurization.

The findings are already being applied in the field. The Wiedmann-Boor Lab was enlisted by Upstate Niagara, a cooperative of more than 360 dairy farm families throughout western New York, to further improve the quality of their award-winning milk by assessing milk samples for spore-formers.

Data on samples that contained spore-forming bacteria are now being analyzed using DNA fingerprinting to identify the types of organisms present and where they might have come from.
Martin said she hopes the collaborative project will become a model for how to approach spore-forming bacteria in individual dairy processing plants.

"It's one of the strengths we have at Cornell -- we are able to do advanced research and immediately turn it around to help the industry," Martin said.

Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,800+ scientific posters on ePosters
  • More than 4,000+ scientific videos on LabTube
  • 35 community eNewsletters

Sign In

Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

On Planes, Savory Tomato Becomes Favored Flavor
Study shows the effect that airplane noise has on passengers' taste preferences.
Friday, May 15, 2015
On the Environmental Trail of Food Pathogens
Learning where Listeria dwells can aid the search for other food pathogens.
Tuesday, December 23, 2014
Ingested Nanoparticles May Damage Liver
Although nanoparticles in food, sunscreen and other everyday products have many benefits, researchers from Cornell are finding that at certain doses, the particles might cause human organ damage.
Tuesday, August 12, 2014
Foodborne Pathogen Detection Speeds Up Dramatically
Next-generation sequencing techniques allow rapidly identification of strains of salmonella, quickening responses to potential outbreaks.
Monday, July 21, 2014
Dairy Farmers Should Alternate Pesticides to Kill Flies
Flies spread disease and a host of pathogens that cost farms hundreds of millions of dollars in annual losses.
Thursday, June 26, 2014
New York Secures $3.4M to Bolster Food Research
Funds will go toward the $13M needed to modernize the Fruit and Vegetable Processing Pilot Plant, Phase I of the proposed $47M Agricultural Science Research Laboratory project.
Thursday, June 26, 2014
Cornell University at Forefront of Dairy Safety Outreach
Cornell’s Food Science Dairy Extension Program faculty and professionals are helping New York cheesemakers and dairy producers provide safe, high-quality products for consumers.
Friday, June 13, 2014
Paving the Way for Better Dietary Zinc Test
Cornell research unveils a new method to test for zinc deficiency, a vital measurement that has posed problems for doctors and scientists.
Friday, April 11, 2014
Senator to Tout Cornell Food Safety, Dairy Expertise to Feds
Cornell University is positioned to be a national center of excellence in dairy and food safety.
Monday, September 09, 2013
New Method Makes Puffed Rice Pop with More Nutrients
Puffed rice just got more snap, crackle and pop, thanks to a new method for making puffed rice that retains nutrients and allows producers to fortify cereals with vitamins and protein.
Wednesday, March 20, 2013
Green Food Labels Make Nutrition-Poor Food Seem Healthy
Consumers to perceive a candy bar as more healthful when it has a green calorie label compared to a red one.
Tuesday, March 12, 2013
Changes in Epigenome Control Tomato Ripening
Everyone loves a juicy, perfectly ripened tomato, and scientists have long sought ways to control the ripening process to improve fruit quality and prevent spoilage.
Wednesday, January 30, 2013
Grant Will Help Reduce Incidence of Johne's Disease in Dairy Cows
Dangerous bacterium in milk could also be linked to Crohn’s disease in humans.
Tuesday, January 08, 2013
Tracing Foodborne Pathogens on the Farm
Remote sensing, microbiology used to trace foodborne pathogens.
Thursday, December 06, 2012
Federal Grants will Fund Study of Food System, Environment
Cornell University grant will help tackle some of the biggest questions in affecting agriculture.
Thursday, November 01, 2012
Scientific News
The MaxSignal Colistin ELISA Test Kit from Bioo Scientific
Kit can help prevent the antibiotic apocalypse by keeping last resort drugs out of the food supply.
Kitchen Utensils Can Spread Bacteria Between Foods
In a recent study researchers found that produce that contained bacteria would contaminate other produce items through the continued use of knives or graters—the bacteria would latch on to the utensils commonly found in consumers' homes and spread to the next item.
GMO Food Animals Should be Judged by Product, Not Process
In a world with a burgeoning demand for meat, milk and eggs, regulatory policies around the use of biotechnologies in agriculture need to be based on the safety and attributes of those foods rather than on the methods used to produce them, says a UC Davis animal scientist.
Acetaldehyde and Formaldehyde Content in Foods
Korean researchers have determined the content of the toxic and carcinogenic aldehydes, acetaldehyde and formaldehyde, in a variety of food groups.
Increasing Vitamin D Supplementation
New study from ETH Zurich finds that elderly women should consume more vitamin D than previously recommended during the winter months.
IARC Monographs Evaluate Consumption of Red Meat and Processed Meat
Processed meat eaten daily increases the risk of colorectal cancer by 18%.
Nanoparticles in Foods Raise Safety Questions
Nanoparticles can make foods like jawbreaker candies brighter and creamier and keep them fresh longer. But researchers are still in the dark about what the tiny additives do once inside our bodies.
Arsenic Found in Many U.S. Red Wines
A new University of Washington study that tested 65 wines from America’s top four wine-producing states — California, Washington, New York and Oregon — found all but one have arsenic levels that exceed what’s allowed in drinking water.
Viruses Join Fight Against Harmful Bacteria
Engineered viruses could combat human disease and improve food safety.
Plastic for Dinner
Roughly a quarter of the fish sampled from fish markets in California and Indonesia contained man-made debris according to a study from the University of California, Davis, and Hasanuddin University in Indonesia.

SELECTBIO Market Reports
Go to LabTube
Go to eposters
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,800+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,000+ scientific videos